The Red Devils have been heavily linked with a move for the France international in recent days as Louis van Gaal looks to bolster his midfield options ahead of his second season in charge at Old Trafford.
Now, it appears that United have stepped up their interest in the midfielder by tabling a £20m bid for the 25-year-old, reports the Daily Telegraph.
However, Southampton are said to have turned down the initial approach, with the south coast club believed to be holding out for a fee in the region of £25m.
The Southampton star, who has also been touted as a possible target for Arsenal in recent weeks, has scored 15 goals in 260 games in all competitions for the south-coast club over the past seven seasons.
Earlier this week, speculation linking the midfielder with a transfer to United gathered pace when the club’s photographer followed the midfielder on Twitter.
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